Aspen System's long-term objective is to develop, optimize, and commercialize a high performance personal cooling system designed to safely protect workers in military, government, commercial and industrial occupations from heat stress and heat-related illness and injury. The cooling system is based on a miniature rotary vapor compressor developed by Aspen. The compressor is integrated with custom refrigeration components into a small, lightweight, mobile man-mountable cooling system. [unreadable] [unreadable] In the Phase 1 program, Aspen will focus on the development and optimization of the cooling unit through development and testing of an advanced thermal control method. Through the implementation of an optimal thermal feedback and control algorithm the vapor-compression cooling unit performance can be improved for increased mission length, reduction in power consumption, and possible reductions in system size and weight. The use of an "intelligent" control algorithm which captures the physiological interaction of the user and cooling garment can lead to improvements in system operability and optimization of the amount of cooling provided feasibility of the most-promising control approach(es). [unreadable] [unreadable] The current program offers the potential for commercialization of a robust vapor-compression personal cooling solution targeted for use by industrial and commercial workers without the logistics burden of existing products. The successful development and fielding of this improved personal cooling product for heat stress prevention allows for greater acceptance and widespread use of personal cooling and directly leads to a reduction in occupational injuries related to heat stress while increasing worker well-being and productivity. The application is of particular benefit to industrial and commercial workers with occupations which routinely expose them to heat-related hazards (HAZMAT) cleanup, mine rescue, firefighters, etc). [unreadable] [unreadable] [unreadable] [unreadable]